This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Impaired perfusion and oxygenation are one of the most frequent causes of healing failure in chronic wounds such peripheral vascular disease, diabetic ulcers and pressure ulcers. These ulcers always require immediate intervention to prevent progression to a more complicated and potentially morbid wound. Thus, development of noninvasive technologies for evaluation of tissue oxygenation and perfusion of the wound is essential for optimizing therapeutic treatments of chronic wounds. The central aim of this project is to employ a new NIR imaging method known as modulated imaging, to spatially resolve quantitative maps of tissue hemoglobin content and oxygen saturation in an animal wound model. The modulated Imaging instrument uses patterned illumination to non-invasively obtain subsurface images of biological tissues. This non-contact approach enables rapid quantitative determination of the optical properties of the biological tissues over a wide field-of-view. When combined with multi-spectral imaging, the optical properties at several wavelengths provide quantitative measures within tissues to determine the in-vivo concentrations of chromophores, namely, oxy- and deoxy-hemoglobin. Furthermore, images at various spatial frequencies can be processed to visualize depth-sectioned subsurface features in terms of scattering and absorption. Furthermore, images at various spatial frequencies can be processed to visualize depth-sectioned subsurface features in terms of scattering and absorption. Our hypothesis is that the NIR-based modulated imaging instrument can effectively work as a tissue oxygenation imager or Oximager for quantitative assessment of hemoglobin content and oxygenation within ischemic chronic wounds of superficial tissues.